Whey is the fluid left over when milk is made into cheese. It is used in everything from ricotta to the popular Swiss soft-drink Rivella.

The Western world didn’t start using whey until the 1950s, when farmers noticed that weeds growing along streams near cheese-making factories were unusually strong. The waste from cheese factories was first used as fertilizer, before scientists confirmed that this by-product was healthy.

But it took modern society some time to discover its nutritional value. Hippocrates is said to have drunk whey. Little Miss Muffet, from the famous nursery rhyme, actually did “[sit] on her tuffet, eating some curds and whey” in the 17th century.

Interestingly, whey contains the same proteins as human milk, which are distinct from the protein found in cow’s milk. As a result, whey is an important ingredient in baby formula.

Isolating the protein content of whey produces whey protein, which is extremely popular in the body-building world. Whey protein is also an important ingredient in protein shakes and post-workout recovery foods, because it is easily digestible and thus efficiently absorbed by muscles.

The health benefits of whey are further illustrated by a study published in The American Journal of Clinical Nutrition in 2005 which showed that when consumed as part of a high-glycemic-index meal, whey promoted the release of insulin. Thus, whey may be beneficial for individuals suffering from Type 2 diabetes.

In addition, the presence of branched-chain amino acids, or BCAAs, in whey is also significant, since BCAAs play a key role in metabolism.

Whey is useful as a food additive thanks to its ability to bind water and prevent food from going stale. As a result, whey is essential for evoking cheesiness in cheese-flavored chips, as well as enabling the creaminess in aerosol spray cheese.

In the 1990s, scientists discovered that after forcing whey protein through a high-pressure tube, the resulting microparticles acquired a fat-like texture. As a result, microparticulated whey protein, sold under the brand name Simplesse, is now found as an artificial fat in low-fat cheese products and desserts.

In the past 50 years, whey has gone from being a mere by-product to becoming an essential component of hundreds of foods. Whey’s story shows that what may appear to be waste isn’t always the case!